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2021-06-22block/mq-deadline: Improve the sysfs show and store macrosBart Van Assche1-37/+29
Define separate macros for integers and jiffies to improve readability. Use sysfs_emit() and kstrtoint() instead of sprintf() and simple_strtol(). The former functions are the recommended functions. Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210618004456.7280-11-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/mq-deadline: Improve compile-time argument checkingBart Van Assche1-47/+49
Modern compilers complain if an out-of-range value is passed to a function argument that has an enumeration type. Let the compiler detect out-of-range data direction arguments instead of verifying the data_dir argument at runtime. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210618004456.7280-10-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/mq-deadline: Rename dd_init_queue() and dd_exit_queue()Bart Van Assche1-4/+4
Change "queue" into "sched" to make the function names reflect better the purpose of these functions. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210618004456.7280-9-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/mq-deadline: Remove two local variablesBart Van Assche1-6/+2
Make __dd_dispatch_request() easier to read by removing two local variables. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210618004456.7280-8-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/mq-deadline: Add two lockdep_assert_held() statementsBart Van Assche1-0/+4
Document the locking strategy by adding two lockdep_assert_held() statements. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210618004456.7280-7-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/mq-deadline: Add several commentsBart Van Assche1-0/+18
Make the code easier to read by adding more comments. Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210618004456.7280-6-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block: Introduce the ioprio rq-qos policyBart Van Assche7-0/+299
Introduce an rq-qos policy that assigns an I/O priority to requests based on blk-cgroup configuration settings. This policy has the following advantages over the ioprio_set() system call: - This policy is cgroup based so it has all the advantages of cgroups. - While ioprio_set() does not affect page cache writeback I/O, this rq-qos controller affects page cache writeback I/O for filesystems that support assiociating a cgroup with writeback I/O. See also Documentation/admin-guide/cgroup-v2.rst. Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210618004456.7280-5-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/blk-rq-qos: Move a function from a header file into a C fileBart Van Assche2-13/+13
rq_qos_id_to_name() is only used in blk-mq-debugfs.c so move that function into in blk-mq-debugfs.c. Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Link: https://lore.kernel.org/r/20210618004456.7280-4-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/blk-cgroup: Swap the blk_throtl_init() and blk_iolatency_init() callsBart Van Assche1-5/+4
Before adding more calls in this function, simplify the error path. Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20210618004456.7280-3-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-22block/Kconfig: Make the BLK_WBT and BLK_WBT_MQ entries consecutiveBart Van Assche1-7/+7
These entries were consecutive at the time of their introduction but are no longer consecutive. Make these again consecutive. Additionally, modify the help text since it refers to blk-mq and since the legacy block layer has been removed. Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Link: https://lore.kernel.org/r/20210618004456.7280-2-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-18blk-wbt: remove outdated commentlijiazi1-1/+0
Now wbt_wait() returns void, so remove now outdated comment. Signed-off-by: lijiazi <lijiazi@xiaomi.com> Link: https://lore.kernel.org/r/1623986240-13878-1-git-send-email-lijiazi@xiaomi.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-18block: Remove unnecessary elevator operation checksDamien Le Moal2-7/+10
The insert_requests and dispatch_request elevator operations are mandatory for the correct execution of an elevator, and all implemented elevators (bfq, kyber and mq-deadline) implement them. As a result, there is no need to check for these operations before calling them when a queue has an elevator set. This simplifies the code in __blk_mq_sched_dispatch_requests() and blk_mq_sched_insert_request(). To avoid out-of-tree elevators to crash the kernel in case of bad implementation, add a check in elv_register() to verify that these operations are implemented. A small, probably not significant, IOPS improvement of 0.1% is observed with this patch applied (4.117 MIOPS to 4.123 MIOPS, average of 20 fio runs doing 4K random direct reads with psync and 32 jobs). Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20210618015922.713999-1-damien.lemoal@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-18blk-mq: fix use-after-free in blk_mq_exit_schedMing Lei1-1/+3
tagset can't be used after blk_cleanup_queue() is returned because freeing tagset usually follows blk_clenup_queue(). Commit d97e594c5166 ("blk-mq: Use request queue-wide tags for tagset-wide sbitmap") adds check on q->tag_set->flags in blk_mq_exit_sched(), and causes use-after-free. Fixes it by using hctx->flags. Reported-by: syzbot+77ba3d171a25c56756ea@syzkaller.appspotmail.com Fixes: d97e594c5166 ("blk-mq: Use request queue-wide tags for tagset-wide sbitmap") Cc: John Garry <john.garry@huawei.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Tested-by: John Garry <john.garry@huawei.com> Reviewed-by: John Garry <john.garry@huawei.com> Link: https://lore.kernel.org/r/20210609063046.122843-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-18sched: Change task_struct::statePeter Zijlstra1-1/+1
Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org
2021-06-18sched: Add get_current_state()Peter Zijlstra1-1/+1
Remove yet another few p->state accesses. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210611082838.347475156@infradead.org
2021-06-18sched: Introduce task_is_running()Peter Zijlstra1-1/+1
Replace a bunch of 'p->state == TASK_RUNNING' with a new helper: task_is_running(p). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210611082838.222401495@infradead.org
2021-06-17block: export blk_next_bio()Chaitanya Kulkarni1-0/+1
The block layer provides emulation of zone management operations targeting all zones of a zoned block device only for the zone reset operation (REQ_OP_ZONE_RESET). In order to correctly implement exporting of zoned block devices with NVMeOF, emulating zone management operations targeting all zones of a device is also necessary for the open, close and finish zone operations (REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH). Instead of duplicating the code, export the existing helper from block layer so we can use a bio chaining pattern that is present in the block layer for REQ_OP_ZONE RESET all emulation in the NVMeOF zoned block device backend. Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2021-06-16block: mark queue init done at the end of blk_register_queueMing Lei1-14/+15
Mark queue init done when everything is done well in blk_register_queue(), so that wbt_enable_default() can be run quickly without any RCU period involved since adding rq qos requires to freeze queue. Also no any side effect by delaying to mark queue init done. Reported-by: Yi Zhang <yi.zhang@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Yi Zhang <yi.zhang@redhat.com> Link: https://lore.kernel.org/r/20210609015822.103433-3-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-16block: fix race between adding/removing rq qos and normal IOMing Lei1-0/+24
Yi reported several kernel panics on: [16687.001777] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 ... [16687.163549] pc : __rq_qos_track+0x38/0x60 or [ 997.690455] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 ... [ 997.850347] pc : __rq_qos_done+0x2c/0x50 Turns out it is caused by race between adding rq qos(wbt) and normal IO because rq_qos_add can be run when IO is being submitted, fix this issue by freezing queue before adding/deleting rq qos to queue. rq_qos_exit() needn't to freeze queue because it is called after queue has been frozen. iolatency calls rq_qos_add() during allocating queue, so freezing won't add delay because queue usage refcount works at atomic mode at that time. iocost calls rq_qos_add() when writing cgroup attribute file, that is fine to freeze queue at that time since we usually freeze queue when storing to queue sysfs attribute, meantime iocost only exists on the root cgroup. wbt_init calls it in blk_register_queue() and queue sysfs attribute store(queue_wb_lat_store() when write it 1st time in case of !BLK_WBT_MQ), the following patch will speedup the queue freezing in wbt_init. Reported-by: Yi Zhang <yi.zhang@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Yi Zhang <yi.zhang@redhat.com> Link: https://lore.kernel.org/r/20210609015822.103433-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-11blk-mq: remove blk_mq_init_sq_queueChristoph Hellwig1-22/+0
All users are gone now. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210602065345.355274-16-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-11blk-mq: add the blk_mq_alloc_disk APIsChristoph Hellwig1-0/+19
Add a new API to allocate a gendisk including the request_queue for use with blk-mq based drivers. This is to avoid boilerplate code in drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210602065345.355274-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-11blk-mq: improve the blk_mq_init_allocated_queue interfaceChristoph Hellwig3-24/+15
Don't return the passed in request_queue but a normal error code, and drop the elevator_init argument in favor of just calling elevator_init_mq directly from dm-rq. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210602065345.355274-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-11blk-mq: factor out a blk_mq_alloc_sq_tag_set helperChristoph Hellwig1-14/+18
Factour out a helper to initialize a simple single hw queue tag_set from blk_mq_init_sq_queue. This will allow to phase out blk_mq_init_sq_queue in favor of a more symmetric and general API. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210602065345.355274-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-10scsi: blkcg: Add app identifier support for blkcgMuneendra Kumar1-0/+9
Add a unique application identifier (i.e fc_app_id member) in blkcg. This allows identification of traffic belonging to an specific both on the host and in the fabric infrastructure. As an example, this allows the storage stack to uniquely identify traffic belong to particular virtual machine. Link: https://lore.kernel.org/r/20210608043556.274139-3-muneendra.kumar@broadcom.com Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Muneendra Kumar <muneendra.kumar@broadcom.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-06-09rq-qos: fix missed wake-ups in rq_qos_throttle try twoJan Kara1-2/+2
Commit 545fbd0775ba ("rq-qos: fix missed wake-ups in rq_qos_throttle") tried to fix a problem that a process could be sleeping in rq_qos_wait() without anyone to wake it up. However the fix is not complete and the following can still happen: CPU1 (waiter1) CPU2 (waiter2) CPU3 (waker) rq_qos_wait() rq_qos_wait() acquire_inflight_cb() -> fails acquire_inflight_cb() -> fails completes IOs, inflight decreased prepare_to_wait_exclusive() prepare_to_wait_exclusive() has_sleeper = !wq_has_single_sleeper() -> true as there are two sleepers has_sleeper = !wq_has_single_sleeper() -> true io_schedule() io_schedule() Deadlock as now there's nobody to wakeup the two waiters. The logic automatically blocking when there are already sleepers is really subtle and the only way to make it work reliably is that we check whether there are some waiters in the queue when adding ourselves there. That way, we are guaranteed that at least the first process to enter the wait queue will recheck the waiting condition before going to sleep and thus guarantee forward progress. Fixes: 545fbd0775ba ("rq-qos: fix missed wake-ups in rq_qos_throttle") CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210607112613.25344-1-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-04block: improve handling of all zones reset operationDamien Le Moal1-27/+92
SCSI, ZNS and null_blk zoned devices support resetting all zones using a single command (REQ_OP_ZONE_RESET_ALL), as indicated using the device request queue flag QUEUE_FLAG_ZONE_RESETALL. This flag is not set for device mapper targets creating zoned devices. In this case, a user request for resetting all zones of a device is processed in blkdev_zone_mgmt() by issuing a REQ_OP_ZONE_RESET operation for each zone of the device. This leads to different behaviors of the BLKRESETZONE ioctl() depending on the target device support for the reset all operation. E.g. blkzone reset /dev/sdX will reset all zones of a SCSI device using a single command that will ignore conventional, read-only or offline zones. But a dm-linear device including conventional, read-only or offline zones cannot be reset in the same manner as some of the single zone reset operations issued by blkdev_zone_mgmt() will fail. E.g.: blkzone reset /dev/dm-Y blkzone: /dev/dm-0: BLKRESETZONE ioctl failed: Remote I/O error To simplify applications and tools development, unify the behavior of the all-zone reset operation by modifying blkdev_zone_mgmt() to not issue a zone reset operation for conventional, read-only and offline zones, thus mimicking what an actual reset-all device command does on a device supporting REQ_OP_ZONE_RESET_ALL. This emulation is done using the new function blkdev_zone_reset_all_emulated(). The zones needing a reset are identified using a bitmap that is initialized using a zone report. Since empty zones do not need a reset, also ignore these zones. The function blkdev_zone_reset_all() is introduced for block devices natively supporting reset all operations. blkdev_zone_mgmt() is modified to call either function to execute an all zone reset request. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> [hch: split into multiple functions] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-06-03block: Update blk_update_request() documentationBart Van Assche1-8/+4
Although the original intent was to use blk_update_request() in stacking block drivers only, it is used much more widely today. Reflect this in the documentation block above this function. See also: * commit 32fab448e5e8 ("block: add request update interface"). * commit 2e60e02297cf ("block: clean up request completion API"). * commit ed6565e73424 ("block: handle partial completions for special payload requests"). Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210519175226.8853-1-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-03block: Do not pull requests from the scheduler when we cannot dispatch themJan Kara3-2/+14
Provided the device driver does not implement dispatch budget accounting (which only SCSI does) the loop in __blk_mq_do_dispatch_sched() pulls requests from the IO scheduler as long as it is willing to give out any. That defeats scheduling heuristics inside the scheduler by creating false impression that the device can take more IO when it in fact cannot. For example with BFQ IO scheduler on top of virtio-blk device setting blkio cgroup weight has barely any impact on observed throughput of async IO because __blk_mq_do_dispatch_sched() always sucks out all the IO queued in BFQ. BFQ first submits IO from higher weight cgroups but when that is all dispatched, it will give out IO of lower weight cgroups as well. And then we have to wait for all this IO to be dispatched to the disk (which means lot of it actually has to complete) before the IO scheduler is queried again for dispatching more requests. This completely destroys any service differentiation. So grab request tag for a request pulled out of the IO scheduler already in __blk_mq_do_dispatch_sched() and do not pull any more requests if we cannot get it because we are unlikely to be able to dispatch it. That way only single request is going to wait in the dispatch list for some tag to free. Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210603104721.6309-1-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: remove bdget_diskChristoph Hellwig2-43/+17
Just opencode the xa_load in the callers, as none of them actually needs a reference to the bdev. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210525061301.2242282-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: factor out a part_devt helperChristoph Hellwig1-8/+17
Add a helper to find the dev_t for a disk + partno tuple. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210525061301.2242282-8-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: move bd_part_count to struct gendiskChristoph Hellwig1-1/+1
The bd_part_count value only makes sense for whole devices, so move it to struct gendisk and give it a more descriptive name. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210525061301.2242282-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: move bd_mutex to struct gendiskChristoph Hellwig2-17/+14
Replace the per-block device bd_mutex with a per-gendisk open_mutex, thus simplifying locking wherever we deal with partitions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20210525061301.2242282-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: unexport blk_alloc_queueChristoph Hellwig2-1/+2
blk_alloc_queue is just an internal helper now, unexport it and remove it from the public header. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/r/20210521055116.1053587-27-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: add blk_alloc_disk and blk_cleanup_disk APIsChristoph Hellwig1-0/+35
Add two new APIs to allocate and free a gendisk including the request_queue for use with BIO based drivers. This is to avoid boilerplate code in drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/r/20210521055116.1053587-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: add a flag to make put_disk on partially initalized disks saferChristoph Hellwig1-2/+5
Add a flag to indicate that __device_add_disk did grab a queue reference so that disk_release only drops it if we actually had it. This sort out one of the major pitfals with partially initialized gendisk that a lot of drivers did get wrong or still do. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/r/20210521055116.1053587-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: automatically enable GENHD_FL_EXT_DEVTChristoph Hellwig2-5/+1
Automatically set the GENHD_FL_EXT_DEVT flag for all disks allocated without an explicit number of minors. This is what all new block drivers should do, so make sure it is the default without boilerplate code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/r/20210521055116.1053587-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: move the DISK_MAX_PARTS sanity check into __device_add_diskChristoph Hellwig1-7/+6
Keep this together with the first place that actually looks at ->minors and prepare for not passing a minors argument to alloc_disk. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/r/20210521055116.1053587-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01block: refactor device number setup in __device_add_diskChristoph Hellwig3-66/+49
Untangle the mess around blk_alloc_devt by moving the check for the used allocation scheme into the callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Link: https://lore.kernel.org/r/20210521055116.1053587-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-06-01scsi: core: Drop message byte helperHannes Reinecke1-1/+1
The message byte is now unused, so we can drop the helper to set the message byte and the check for message bytes during error recovery. Link: https://lore.kernel.org/r/20210427083046.31620-38-hare@suse.de Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-06-01scsi: core: Drop the now obsolete driver_byte definitionsHannes Reinecke3-3/+3
The driver_byte field in the result is now unused, so we can drop the definitions. Link: https://lore.kernel.org/r/20210427083046.31620-15-hare@suse.de Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-06-01scsi: core: Kill DRIVER_SENSEHannes Reinecke2-0/+4
Replace the check for DRIVER_SENSE with a check for scsi_status_is_check_condition(). Audit all callsites to ensure the SAM status is set correctly. For backwards compability move the DRIVER_SENSE definition to sg.h, and update sg, bsg, and scsi_ioctl to set the DRIVER_SENSE driver_status whenever SAM_STAT_CHECK_CONDITION is present. [mkp: fix zeroday srp warning] Link: https://lore.kernel.org/r/20210427083046.31620-10-hare@suse.de Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> fix
2021-06-01scsi: scsi_ioctl: Return error code when blk_rq_map_kern() failsHannes Reinecke1-3/+4
The callers of sg_scsi_ioctl() already check for negative return values, so we can drop the usage of DRIVER_ERROR and return the error from blk_rq_map_kern() instead. Link: https://lore.kernel.org/r/20210427083046.31620-3-hare@suse.de Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-05-24blk-mq: Use request queue-wide tags for tagset-wide sbitmapJohn Garry4-21/+72
The tags used for an IO scheduler are currently per hctx. As such, when q->nr_hw_queues grows, so does the request queue total IO scheduler tag depth. This may cause problems for SCSI MQ HBAs whose total driver depth is fixed. Ming and Yanhui report higher CPU usage and lower throughput in scenarios where the fixed total driver tag depth is appreciably lower than the total scheduler tag depth: https://lore.kernel.org/linux-block/440dfcfc-1a2c-bd98-1161-cec4d78c6dfc@huawei.com/T/#mc0d6d4f95275a2743d1c8c3e4dc9ff6c9aa3a76b In that scenario, since the scheduler tag is got first, much contention is introduced since a driver tag may not be available after we have got the sched tag. Improve this scenario by introducing request queue-wide tags for when a tagset-wide sbitmap is used. The static sched requests are still allocated per hctx, as requests are initialised per hctx, as in blk_mq_init_request(..., hctx_idx, ...) -> set->ops->init_request(.., hctx_idx, ...). For simplicity of resizing the request queue sbitmap when updating the request queue depth, just init at the max possible size, so we don't need to deal with the possibly with swapping out a new sbitmap for old if we need to grow. Signed-off-by: John Garry <john.garry@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/1620907258-30910-3-git-send-email-john.garry@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24blk-mq: Some tag allocation code refactoringJohn Garry3-25/+40
The tag allocation code to alloc the sbitmap pairs is common for regular bitmaps tags and shared sbitmap, so refactor into a common function. Also remove superfluous "flags" argument from blk_mq_init_shared_sbitmap(). Signed-off-by: John Garry <john.garry@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/1620907258-30910-2-git-send-email-john.garry@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24blk-mq: clearing flush request reference in tags->rqs[]Ming Lei1-1/+34
Before we free request queue, clearing flush request reference in tags->rqs[], so that potential UAF can be avoided. Based on one patch written by David Jeffery. Tested-by: John Garry <john.garry@huawei.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: David Jeffery <djeffery@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210511152236.763464-5-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24blk-mq: clear stale request in tags->rq[] before freeing one request poolMing Lei3-7/+54
refcount_inc_not_zero() in bt_tags_iter() still may read one freed request. Fix the issue by the following approach: 1) hold a per-tags spinlock when reading ->rqs[tag] and calling refcount_inc_not_zero in bt_tags_iter() 2) clearing stale request referred via ->rqs[tag] before freeing request pool, the per-tags spinlock is held for clearing stale ->rq[tag] So after we cleared stale requests, bt_tags_iter() won't observe freed request any more, also the clearing will wait for pending request reference. The idea of clearing ->rqs[] is borrowed from John Garry's previous patch and one recent David's patch. Tested-by: John Garry <john.garry@huawei.com> Reviewed-by: David Jeffery <djeffery@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210511152236.763464-4-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iterMing Lei3-16/+43
Grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter(), and this way will prevent the request from being re-used when ->fn is running. The approach is same as what we do during handling timeout. Fix request use-after-free(UAF) related with completion race or queue releasing: - If one rq is referred before rq->q is frozen, then queue won't be frozen before the request is released during iteration. - If one rq is referred after rq->q is frozen, refcount_inc_not_zero() will return false, and we won't iterate over this request. However, still one request UAF not covered: refcount_inc_not_zero() may read one freed request, and it will be handled in next patch. Tested-by: John Garry <john.garry@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210511152236.763464-3-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24block: avoid double io accounting for flush requestMing Lei1-2/+1
For flush request, rq->end_io() may be called two times, one is from timeout handling(blk_mq_check_expired()), another is from normal completion(__blk_mq_end_request()). Move blk_account_io_flush() after flush_rq->ref drops to zero, so io accounting can be done just once for flush request. Fixes: b68663186577 ("block: add iostat counters for flush requests") Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: John Garry <john.garry@huawei.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210511152236.763464-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24block: remove unneeded parenthesis from blk-sysfsMax Gurtovoy1-8/+8
Align to common code conventions. Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com> Link: https://lore.kernel.org/r/20210511155319.1885277-1-mgurtovoy@nvidia.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-24blkcg: drop CLONE_IO check in blkcg_can_attach()Tejun Heo1-27/+0
blkcg has always rejected to attach if any of the member tasks has shared io_context. The rationale was that io_contexts can be shared across different cgroups making it impossible to define what the appropriate control behavior should be. However, this check causes more problems than it solves: * The check prevents controller enable and migrations but not CLONE_IO itself, which can lead to surprises as the outcome changes depending on the order of operations. * Sharing within a cgroup is fine but the check can't distinguish that. This leads to unnecessary conflicts with the recent CLONE_IO usage in io_uring. io_context sharing doesn't make any difference for rq_qos based controllers and the way it's used is safe as long as tasks aren't migrated dynamically which is the vast majority of use cases. While we can try to make the check more precise to avoid false positives, the added complexity doesn't seem worthwhile. Let's just drop blkcg_can_attach(). Signed-off-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/YJrTvHbrRDbJjw+S@slm.duckdns.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
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